Zhu Hongzheng, Prasad Anil, Doja Somi, Bichler Lukas, Liu Jian
School of Engineering, Faculty of Applied Science, The University of British Columbia, Kelowna, BC V1V 1V7, Canada.
Nanomaterials (Basel). 2019 Jul 29;9(8):1086. doi: 10.3390/nano9081086.
Sodium superionic conductor (NASICON)-type lithium aluminum germanium phosphate (LAGP) has attracted increasing attention as a solid electrolyte for all-solid-state lithium-ion batteries (ASSLIBs), due to the good ionic conductivity and highly stable interface with Li metal. However, it still remains challenging to achieve high density and good ionic conductivity in LAGP pellets by using conventional sintering methods, because they required high temperatures (>800 °C) and long sintering time (>6 h), which could cause the loss of lithium, the formation of impurity phases, and thus the reduction of ionic conductivity. Herein, we report the utilization of a spark plasma sintering (SPS) method to synthesize LAGP pellets with a density of 3.477 g cm, a relative high density up to 97.6%, and a good ionic conductivity of 3.29 × 10 S cm. In contrast to the dry-pressing process followed with high-temperature annealing, the optimized SPS process only required a low operating temperature of 650 °C and short sintering time of 10 min. Despite the least energy and short time consumption, the SPS approach could still achieve LAGP pellets with high density, little voids and cracks, intimate grain-grain boundary, and high ionic conductivity. These advantages suggest the great potential of SPS as a fabrication technique for preparing solid electrolytes and composite electrodes used in ASSLIBs.
钠超离子导体（NASICON）型磷酸锂铝锗（LAGP）作为全固态锂离子电池（ASSLIBs）的固体电解质，因其良好的离子导电性和与锂金属的高度稳定界面而受到越来越多的关注。然而，使用传统烧结方法在LAGP颗粒中实现高密度和良好的离子导电性仍然具有挑战性，因为这些方法需要高温（>800°C）和长时间烧结（>6小时），这可能导致锂的损失、杂质相的形成，从而降低离子导电性。在此，我们报道了利用火花等离子体烧结（SPS）方法合成密度为3.477 g/cm³、相对密度高达97.6%且离子电导率为3.29×10⁻³ S/cm的LAGP颗粒。与随后进行高温退火的干压工艺相比，优化后的SPS工艺仅需650°C的低操作温度和10分钟的短烧结时间。尽管能量消耗最少且时间短，但SPS方法仍能制备出具有高密度、几乎没有孔隙和裂纹、晶粒-晶界紧密以及高离子导电性的LAGP颗粒。这些优点表明SPS作为一种制备用于ASSLIBs的固体电解质和复合电极的制造技术具有巨大潜力。
